For the most part, I consider questions about politics in a historical context to be politics and therefore on-topic. However, there is a class of questions, which for lack of a better name, I'll call trivia. These are questions like
- Who is the person in this picture?
- Where is a document fitting this description?
If these are about current events and associated with a government or political body, I think that these things should be on-topic. They are only tangentially related to politics, but let's be honest. The people here are more likely to know the answers to these questions than the average person. So they make sense here.
If the same questions are not about current events but about historical events, say from the United States Civil War, then we stop knowing more about them than the average educated person. And there is a stack where people congregate who do know more about historical events than the average educated person. So we should leave historical trivia off topic unless it is political in nature.
When I say political in nature, I mean that it regards things like how different interests are balanced; how agreement is reached; who can exercise power. But politics is not everything that a government or politician did in history. For example, an order issued by a general in 1865 is not political. It was a military decision. However, if the same order were given today, it would be political now.
The reason is that current events are subject to political analysis in regards to things that might happen. For example, President Donald Trump might overrule a military order with his own executive order. Or Congress could pass a law overruling the order. Thus, understanding current events has a political nexus even when the event itself may be made by a non-political actor.
Some historical events may also be current events. For example, Roe v. Wade still has relevance in the ongoing abortion controversy. Thus, discussing Roe is topical even though it is old enough to be historical. Similarly, Lochner v. New York is topical in that it established the penumbra rights concept used in Griswold v. Connecticut and Roe. Also, the impeachment of Andrew Johnson and non-impeachment of Richard Nixon are topical because they set precedents related to the potential impeachment of Trump.
A discussion of how democracy worked in ancient Rome is topical, because someone might want to consider setting up a similar system of government now. But a question asking who was the Tribune in 70 B.C. is not topical but historical.
Political Science is timeless. A form of a government that was in use two thousand years ago is still available today. But the actions of that government are not inherently on-topic the way that current actions are.